Going to hit it with a hammer!!

[Alibert]

Is the CTC another Replicator clone? If so, did you calibrate the extruder? I ask because this jumped out at me:

"feedDiameter" : 1.769999980926514,
         "feedstockMultiplier" : 0.930,

Those two settings partly neutralize each other. Translated to 1.75mm the feedmultiplier is 0.978 which seems to be OK. I use 0.900 - 0.950 for PLA on my machines with good results. ( I also use 1.00 for ABS and 0.98 for PETG by the way).

[Sebastian Finke]

Those two settings partly neutralize each other. Translated to 1.75mm the feedmultiplier is 0.978 which seems to be OK. I use 0.900 - 0.950 for PLA on my machines with good results. ( I also use 1.00 for ABS and 0.98 for PETG by the way).

Very odd. On my machine (FFCX) with Makerware and a filament diameter of 1.75mm I have to set my feedstockmultiplier to 1.05...